The Interstellar Medium
... First idea was to have a debate on relativity: As to relativity, I must confess that I would rather have a subject in which there would be a half dozen members of the Academy competent enough to understand at least a few words of what the speakers were saying if we had a symposium upon it. I pray to ...
... First idea was to have a debate on relativity: As to relativity, I must confess that I would rather have a subject in which there would be a half dozen members of the Academy competent enough to understand at least a few words of what the speakers were saying if we had a symposium upon it. I pray to ...
Lecture 2 Abundances
... • Elements with differences greater than 25% (Table 5, Lodders 2009) are W (2.76), Ag (0.52), Cl (1.79), Rb(1.64), Ga (0.61), Au(1.54). Tl (1.43), Hf (1.43), and F (1.32). Some, like Au, Hf, Mn, and W have uncertain oscillator strengths and problems with line blending. Others, like Cl, Ga, and Rb ar ...
... • Elements with differences greater than 25% (Table 5, Lodders 2009) are W (2.76), Ag (0.52), Cl (1.79), Rb(1.64), Ga (0.61), Au(1.54). Tl (1.43), Hf (1.43), and F (1.32). Some, like Au, Hf, Mn, and W have uncertain oscillator strengths and problems with line blending. Others, like Cl, Ga, and Rb ar ...
Death of sun
... Low mass red dwarf stars cannot achieve any advanced fusion because they cannot get hot enough (Temp < 100 million K) to begin the next reaction (helium to carbon) Hydrogen => Helium fusion ends at core Star shrinks to form a white dwarf ...
... Low mass red dwarf stars cannot achieve any advanced fusion because they cannot get hot enough (Temp < 100 million K) to begin the next reaction (helium to carbon) Hydrogen => Helium fusion ends at core Star shrinks to form a white dwarf ...
PowerPoint Template
... • Do the nearby or the bright stars provide a more typical example of the star population within the Milky Way Galaxy? • Would you expect the same percentage of stars to occupy each branch of the diagram if all stars within the Milky Way Galaxy were plotted? ...
... • Do the nearby or the bright stars provide a more typical example of the star population within the Milky Way Galaxy? • Would you expect the same percentage of stars to occupy each branch of the diagram if all stars within the Milky Way Galaxy were plotted? ...
Document
... collide with and move past one another, while in gases the atoms or molecules are free to move ...
... collide with and move past one another, while in gases the atoms or molecules are free to move ...
Lecture 18
... We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters ...
... We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters ...
ASTR100 Class 01 - University of Maryland Astronomy
... Expansion of universe has redshifted thermal radiation from that time to ~1,000 times longer wavelength: microwaves. ...
... Expansion of universe has redshifted thermal radiation from that time to ~1,000 times longer wavelength: microwaves. ...
Kein Folientitel
... Nuclei can be very well described as an interacting boson system due to the strong pairing between like nucleons. What is the role of the proton-neutron interaction and the other nucleons? Does a neutron and a proton form a paired state with T= 1 and T=0? Does there exist a even-even nuclei with a g ...
... Nuclei can be very well described as an interacting boson system due to the strong pairing between like nucleons. What is the role of the proton-neutron interaction and the other nucleons? Does a neutron and a proton form a paired state with T= 1 and T=0? Does there exist a even-even nuclei with a g ...
Stellar Masses and the Main Sequence
... integrate reaction rate cross-sections over the Maxwellian distribution. The cross sections are energy dependent, since they depend on momentum and tunneling. ...
... integrate reaction rate cross-sections over the Maxwellian distribution. The cross sections are energy dependent, since they depend on momentum and tunneling. ...
Stars - Red, Blue, Old, New pt.2
... • Most stars have temps between 3000 K and 30,000 K. • Stars have wide range in luminosity. Some are 10s of 1000s of times more luminous than sun; others much less luminous. • Masses range from 0.07 to 120 times mass of sun • Diameters planet-sized to 100s x sun ...
... • Most stars have temps between 3000 K and 30,000 K. • Stars have wide range in luminosity. Some are 10s of 1000s of times more luminous than sun; others much less luminous. • Masses range from 0.07 to 120 times mass of sun • Diameters planet-sized to 100s x sun ...
Objectives: 1.
... • The only two atoms that are created as a direct result of the big bang are the two simplest. H and He • Gravity begins to work on this matter forming large gaseous clouds of Hydrogen and Helium. • The gaseous clouds will form the first stars in the universe. • Big bang predicts a ration of 75% Hyd ...
... • The only two atoms that are created as a direct result of the big bang are the two simplest. H and He • Gravity begins to work on this matter forming large gaseous clouds of Hydrogen and Helium. • The gaseous clouds will form the first stars in the universe. • Big bang predicts a ration of 75% Hyd ...
life cycles of stars
... Helium fusion does not begin right away because it requires higher temperatures than hydrogen fusion—larger charge leads to greater repulsion Fusion of two helium nuclei doesn’t work, so helium fusion must combine three He nuclei to make carbon ...
... Helium fusion does not begin right away because it requires higher temperatures than hydrogen fusion—larger charge leads to greater repulsion Fusion of two helium nuclei doesn’t work, so helium fusion must combine three He nuclei to make carbon ...
ASTRONOMY 5
... (Edited for questions relevant to Astronomy 5 2007 Final) Follow the directions in each section. Write all answers on this examination paper. Feel free to ask for clarification of any question. You may utilize the textbook, lecture notes, your notes, homework solutions, and any handouts that we have ...
... (Edited for questions relevant to Astronomy 5 2007 Final) Follow the directions in each section. Write all answers on this examination paper. Feel free to ask for clarification of any question. You may utilize the textbook, lecture notes, your notes, homework solutions, and any handouts that we have ...
Unit 11: Stellar Evolution
... elements heavier than helium. Following these stars’ explosive deaths, these elements, along with even more massive nuclei produced in the explosions themselves, were blasted into interstellar space, enriching the primordial hydrogen and helium with heavier elements. This enriched interstellar mater ...
... elements heavier than helium. Following these stars’ explosive deaths, these elements, along with even more massive nuclei produced in the explosions themselves, were blasted into interstellar space, enriching the primordial hydrogen and helium with heavier elements. This enriched interstellar mater ...
Stellar Masses and the Main Sequence
... integrate reaction rate cross-sections over the Maxwellian distribution. The cross sections are energy dependent, since they depend on momentum and tunneling. ...
... integrate reaction rate cross-sections over the Maxwellian distribution. The cross sections are energy dependent, since they depend on momentum and tunneling. ...
the life cycle of stars - North American Montessori Center
... • Each year, the Milky Way creates about seven new stars. • A supernova occurs about once every 50 years in the Milky Way galaxy. Many supernovas occur that are not visible from the earth, but since the last one observed from earth occurred in 1604, the next visible supernova is overdue. ...
... • Each year, the Milky Way creates about seven new stars. • A supernova occurs about once every 50 years in the Milky Way galaxy. Many supernovas occur that are not visible from the earth, but since the last one observed from earth occurred in 1604, the next visible supernova is overdue. ...
Handout 30
... As the helium core becomes hotter, it transfers energy into a thin shell of hydrogen surrounding the core. As it gets hotter the outer hydrogen shell will emit more energy causing the star to expand to be a giant. ...
... As the helium core becomes hotter, it transfers energy into a thin shell of hydrogen surrounding the core. As it gets hotter the outer hydrogen shell will emit more energy causing the star to expand to be a giant. ...
IsotopeGeochemistry Chapter1 - Earth and Atmospheric Sciences
... that much of the northern hemisphere was once covered by glaciers was first advanced by Swiss zoologist Louis Agassiz in 1837. His theory was based on observations of geomorphology and modern glaciers. Over the next 100 years, this theory advanced very little, other than the discovery that there had ...
... that much of the northern hemisphere was once covered by glaciers was first advanced by Swiss zoologist Louis Agassiz in 1837. His theory was based on observations of geomorphology and modern glaciers. Over the next 100 years, this theory advanced very little, other than the discovery that there had ...
Ay 102: Homework 5 (Blast waves, Supernova Remnant) S. R. Kulkarni
... Please come to the class reading either Ch 38-39 of Draine or 16.1-16.3 of Kowk. I would like that each of be prepared to work out successive elements of this “homework” on the board (with constructive help from me). 1. Supernova Remnant. A popular model for a type Ia supernova is one where a C+O wh ...
... Please come to the class reading either Ch 38-39 of Draine or 16.1-16.3 of Kowk. I would like that each of be prepared to work out successive elements of this “homework” on the board (with constructive help from me). 1. Supernova Remnant. A popular model for a type Ia supernova is one where a C+O wh ...
The Life Cycles of Stars
... waves. If the radio waves are emitted in pulses (due to the star’s spin), these neutron stars are called pulsars. The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova. No nuclear fusion is taking place to support the core, so it is swallowed by ...
... waves. If the radio waves are emitted in pulses (due to the star’s spin), these neutron stars are called pulsars. The core of a massive star that has 8 or more times the mass of our Sun remains massive after the supernova. No nuclear fusion is taking place to support the core, so it is swallowed by ...
When were some of the first elements discovered? Ten elements
... When a beam of alpha particles is directed at a thin gold foil, most particles pass through the foil undeflected, but a small number are deflected at large angles and a few bounce back toward the particle source. But what is an alpha particle? ...
... When a beam of alpha particles is directed at a thin gold foil, most particles pass through the foil undeflected, but a small number are deflected at large angles and a few bounce back toward the particle source. But what is an alpha particle? ...
B/W
... Sun and interstellar medium Typically: Hydrogen 90% by number; Helium 10%; other elements (metals) ¿ 1 % (by mass: X ' 0.70, Y ' 0.28, Z ' 0.02) • Globular cluster stars: Metal deficient compared to Sun by factors of 10 – 1000, Hydrogen and helium normal Assuming uniform initial composition for the ...
... Sun and interstellar medium Typically: Hydrogen 90% by number; Helium 10%; other elements (metals) ¿ 1 % (by mass: X ' 0.70, Y ' 0.28, Z ' 0.02) • Globular cluster stars: Metal deficient compared to Sun by factors of 10 – 1000, Hydrogen and helium normal Assuming uniform initial composition for the ...
Nuclear Physics
... A nucleon is a general term to denote a nuclear particle - that is, either a proton or a neutron. The atomic number Z of an element is equal to the number of protons in the nucleus of that element. The mass number A of an element is equal to the total number of nucleons (protons + neutrons). The mas ...
... A nucleon is a general term to denote a nuclear particle - that is, either a proton or a neutron. The atomic number Z of an element is equal to the number of protons in the nucleus of that element. The mass number A of an element is equal to the total number of nucleons (protons + neutrons). The mas ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.